中国科学院机构知识库网格系统: 检索

Comparison of radiation temperature measurement precision between middlewave and longwave thermal-imaging systems (EI CONFERENCE) 会议论文 OAI收割
2012 International Conference on Optoelectronics and Microelectronics, ICOM 2012, August 23, 2012 - August 25, 2012, Changchun, China
作者: Sun Z.

收藏 | 浏览/下载：28/0 | 提交时间：2013/03/25

A comparison study on temperature measurement precision between middlewave 3-5m and longwave 8-12m measuring thermal imaging systems has been conducted. The study was limited to systems working in indoor conditions and the target's temperature is in the range of 270K900K. First the Disturb Resisting Function (DRF) of infrared systems is deduced. On the base of DRF curve we find that the middlewave infrared system get the smaller influences under the same size disturb compared with the longwave system. A theory of the influence of target's physical characteristic and measurement conditions on the accuracy of temperature measurements has been developed. On the basis of the developed formulas an analysis of the influence of signal disturbances (because of incorrectly assumed emissivity limited transmittance of the atmosphere radiation reflected by the object and shift of optics radiation) on the accuracy of temperature measurement has been made. It has been found that the middlewave systems in typical temperature range offer generally better accuracy in temperature measurement than the longwave ones do. 2012 IEEE.

Modeling and variable structure control of a vehicle flexible manipulator (EI CONFERENCE) 会议论文 OAI收割
10th World Congress on Intelligent Control and Automation, WCICA 2012, July 6, 2012 - July 8, 2012, Beijing, China
作者: Wang Z.; Li Y.; Li Y.; Li Y.; Li Y.

收藏 | 浏览/下载：23/0 | 提交时间：2013/03/25

In this paper the mathematical modeling and the application of a new trajectory tracking control technique for hydraulic-driven rigid-flexible manipulator are concerned. To get a closer dynamic behavior of the real system both the flexible manipulator linkage and the actuator dynamics are considered. The exact dynamic model of flexible manipulator is derived using Lagrange principle and assumed modes method. The partial decoupled dynamic equation is derived using nonlinear decoupling feedback control method. The whole dynamic model is established by a driven Jacobin matrix which represents the coupling between hydraulic servo system and mechanical system. A variable structure controller with inverse dynamics is designed for trajectory tracking. To weaken the chattering of control signal saturation function is used to instead of sign function. The experimental results investigate the effectiveness of the proposed approaches. 2012 IEEE.

General criteria of material instabilities 会议论文 OAI收割
23rd International Congress of Theoretical and Applied Mechanics, 中国北京/Beijing, China, 2012-08-19
作者: Ma W(马维)

收藏 | 浏览/下载：26/0 | 提交时间：2014/04/02

material criteria General workhardening general three instability loading estimate dimensional assumed well thermal detail derived analysis shear strain linear rates

Space optical remote sensor of the CAE thermal control index calculation method (EI CONFERENCE) 会议论文 OAI收割
2011 International Conference on Advanced Design and Manufacturing Engineering, ADME 2011, September 16, 2011 - September 18, 2011, Guangzhou, China
作者: Li L.

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The thermal control indicators CAE methods of Space optical remote sensor are analyzed in the presented work. We sat up a thermal optical analysis model for space optical remote sensor. By assuming fully covered by in-orbit temperature load and using the finite element method for thermal deformation analysis we obtained the optical remote sensor surface deformation and displacement under various thermal loading. Using ZERNIKE polynomial wave was fitted to obtain ZERNIKE polynomial coefficients which were incorporated into the optical system design. Using CODE V optical calculation software heat-ray machines under elastic deformation of the system point spread function transfer function (MTF) wave front differential (WFE) etc. were calculated. Image quality changes of remote sensors are discussed in variety assumed cases such as temperature loads of quality change. By repeated iteration critical value of temperature fields meeting the design requirements are obtained for the optical system. Optical indicators were converged to the temperature field indicator then reasonable indicators of thermal control for remote sensors were obtained. For the thermal control design this method provided a reliable basis for design. (2011) Trans Tech Publications Switzerland.

Chirp estimation of PZT for integrating-bucket method (EI CONFERENCE) 会议论文 OAI收割
5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, April 26, 2010 - April 29, 2010, Dalian, China
作者: Zhang J.; Liu W.; Zhang J.; Zhang J.

收藏 | 浏览/下载：26/0 | 提交时间：2013/03/25

The nonlinear response of the PZT for the integrating bucket method is studied by our proposed method: discrete chirp Fourier transform (DCFT) and maximum likelihood estimation (MLE) techniques for the integrating bucket method. Based on the signal processing theory the intensity obtained from CCD is processed by the DCFT and thus nonlinear response and chirp coefficient of the PZT can be coarsely estimated. This is followed by the MLE method in which an iterative optimization process is complemented for accurately estimating the nonlinear response and chirp coefficient of the PZT. One key advantage of the proposed method is that not only the nonlinear response and chirp coefficient of the PZT can be acquired but also initial phase acquired. Our method is tested by simulating conditions under which a certain magnitude of nonlinearity is assumed. Nonlinear response attained by the DCFT is compared to that attained by the MLE and a difference between the actual nonlinear response of the PZT and our accurate estimation by the proposed method is revealed. Several factors that will have influence on the nonlinear response of the PZT are discussed. 2010 Copyright SPIE - The International Society for Optical Engineering.

Electron transport in polymer-derived amorphous silicon oxycarbonitride ceramics (EI CONFERENCE) 会议论文 OAI收割
作者: Zhang L.; Wang Y.; Wang Y.; Wang Y.; Wang Y.

收藏 | 浏览/下载：65/0 | 提交时间：2013/03/25

The electron transport behavior of polymer-derived amorphous silicon oxycarbonitride ceramics is studied by measuring their temperature-dependent electrical conductivities. The experimental results are analyzed using theoretical models. The results reveal that the materials exhibit three conduction mechanisms: conduction in extended states conduction in band tails and conduction in localized states. Particularly it is found that in a low-temperature regime the conduction of the materials follows a band tail hopping mechanism rather than the previously assumed variable range hopping mechanism. The results also reveal that energy gaps such as EC-E F and EC-EA decrease with increasing pyrolysis temperature. 2009 The American Ceramic Society.

Narcissus analysis for cooled staring IR system (EI CONFERENCE) 会议论文 OAI收割
3rd International Symposium on Advanced Optical Manufacturing and Testing Technologies, AOMATT 2007: Advanced Optical Manufacturing Technologies, July 8, 2007 - July 12, 2007, Chengdu, China
作者: Zhang X.; Zhang X.; Zhang X.

收藏 | 浏览/下载：26/0 | 提交时间：2013/03/25

Narcissus can have a deleterious effect on image quality for cooled infrared imaging systems. Therefore analysis of narcissus is important for designing both scanning and staring optics. Narcissus is generally assumed to be negligible in staring IR optical designs because the shading effects can be removed by calibration of the detector array data. However the calibration usually decreases sensitiveness of the system and Narcissus variation may be noticeable for sensors when the conditions changes as follows: 1. warming and cooling the optical housing 2. zooming optical elements 3. movement of lenses for focus. In that case it will result in shading and other image defects even after calibration. To minimize these effects narcissus should be assessed and controlled during the design of staring array IR system. We provided a direct and fast method for analyzing the narcissus variation in the presence of software such as LightTools TracePro and ASAP and proposed the principles in optical design of staring IR systems to reduce narcissus. A cooled staring IR system with serious narcissus was estimated and reoptimized. Narcissus analysis of this IR system confirmed the efficiency of the analysis method.

Effects of Underfill's Filling Situation on the Reliability of Flip-chip Packages 会议论文 OAI收割
Fourth International Symposium on Electronic Packaging Technology, 北京/Beijing, China, 2001-8-8
作者: Liu S; Zhao YP(赵亚溥); Zhao YP(赵亚溥); Liu S; Liu S

收藏 | 浏览/下载：16/0 | 提交时间：2014/02/14

solder underfill filled 0 outmost substrate 0 fatigue Package understand joints thermal lives 0 silicon reliability range 0 different smaller corners studied assumed simulation

STATIC AND SPHERICALLY SYMMETRIC DYON SOLUTIONS IN SU(N) GAUGE THEORY 期刊论文 OAI收割
A Monthly Journal of Science, 1983, 期号: 1, 页码: 328-332
作者: Ma ZQ(马中骐)

收藏 | 浏览/下载：9/0 | 提交时间：2015/12/10

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ON YANG'S SPHERICALLY SYMMETRIC;STATIC GRAVITATIONAL FIELD 期刊论文 OAI收割
Science in China;Ser.A, 1976, 期号: 2, 页码: 199-206
作者: Chen S(陈时); He ZX(何祚庥); Guo HY(郭汉英); Zou ZL(邹振隆)

收藏 | 浏览/下载：11/0 | 提交时间：2015/12/07

Einstein gravitational rigorous ordinary collapse anisotropic correspond symmetric satisfy assumed